1. Field of the Invention
The present invention relates to a coating and developing system for coating a substrate, such as a semiconductor wafer or an LCD substrate, namely, a glass substrate for a liquid crystal display, with a resist solution by a coating process and processing the substrate by a developing process after exposure, a coating and developing method to be carried out by the coating and developing system, and a storage medium storing a program for carrying out the coating and developing method.
2. Description of the Related Art
A manufacturing process for manufacturing a semiconductor device or an LCD substrate forms a resist patter on a substrate by photolithography. Photolithography includes a series of steps of coating a surface of a substrate, such as a semiconductor wafer (hereinafter, referred to as “wafer”) with a resist film by applying a resist solution to the surface, exposing the resist film to light through a photomask, and processing the exposed resist film by a developing process to form a desired pattern.
Generally, those processes are carried out by a resist pattern forming system constructed by connecting an exposure system to a coating and developing system for coating a surface of a substrate with a resist solution and developing an exposed film. Such a resist pattern forming system is proposed in, for example, JP-A 2004-193597. Referring to FIG. 15 showing this known resist pattern forming system, a carrier 10 containing a plurality of wafers W is delivered to a carrier stage 11 included in a carrier block 1A, and a transfer arm 12 transfers the wafer W contained in the carrier 10 to a processing block 1B. Then, the wafer W is carried in the processing block 1B along a route passing a first temperature control unit, an antireflection film forming unit, and a first heating unit in that order to form an antireflection film on a surface of the wafer W.
Subsequently, the wafer W is carried along a route passing a second temperature control unit, a coating unit, a second heating unit and a cooling unit in that order to form a resist film on the surface of the antireflection film. Then, the wafer W is carried through an interface block 1 to a developing system 1D. The wafer W is returned to the processing block 1B after being processed by an exposure process. Then, the wafer W is processed by a developing process in a developing unit 13B, and then the wafer W is returned to the carrier 10. The antireflection film forming unit, not shown, is disposed under the coating unit 13A or the developing unit 13B.
The first and the second heating unit, the first and the second temperature control unit, the cooling unit and transfer stages are stacked in layers in shelf units 14 (shelf units 14a to 14c). Two carrying devices 15A and 15B installed in the processing block 1B carry the wafer W in the processing block 1B from one to other of modules that receive the wafer W, such as the antireflection film forming unit, the coating unit 13A, the developing unit 13, and component units of the shelf units 14a to 14c to subject the wafer W. The wafer W is subjected to the foregoing processes. As mentioned in JP-A 2004-193597, wafers W to be subjected to the foregoing processes are carried to the modules according to a carrying schedule defining times when the wafers W are carried to the modules, respectively.
In some cases, wafers A of a preceding lot A and wafers B of a succeeding lot B are delivered successively from the carrier block 1A to the processing block 1B to process the wafers A and the wafers B, and the wafers A and the wafers B are processed by a heating process by the second heating unit at different temperatures, respectively. In the heating process, a wafer is mounted on, for example, a heating plate heated at a predetermined temperature. The heating temperature of the heating process is changed by changing a set temperature at which the heating plate is to be heated.
When the process temperature of the second heating unit needs to be changed, the wafers A and B are carried according to a carrying schedule including the steps of withholding the delivery of the first wafer B1 of the lot B from the carrier block 1A to the processing block 1B after the last wafer A10 of the lot A has been delivered from the carrier block 1A to the processing block 1B, starting changing the process temperature of the second heating unit after the last wafer A10 processed by the second heating unit has been transferred to the next unit, and starting the first wafer B1 from the carrier block 1A to the processing block 1B after the completion of changing the process temperature of the second heating unit.
Since the transfer of the wafers B of the lot B to the processing block 1B is withheld until the completion of changing the process temperature of the second heating unit, the processing block 1B can not process the wafers B during the operation for changing the process temperature of the second heating unit. If changing the process temperature of the second heating unit takes a long time, the wafers B held for a long time without being processed and, consequently, the throughput of the resist pattern forming system reduces.
The through put of the exposure system has increased in recent years and the processing capacity of the coating and developing system is required to be compatible with the increased throughput of the developing system. The inventors of the present invention have made efforts to reduce load on the carrying devices, to improve carrying efficiency and to increase the throughput of the coating and developing system by stacking up an area in which the modules for processing the wafer before the wafer is subjected to an exposure process are arranged, and an area in which the modules for processing the wafer processed by the exposure process are arranged, and installing carrying devices in those areas, respectively. A system having a coating area for a coating process and a developing area for developing process stacked one on top of the other, and carrying devices respectively installed in the coating area and the developing area is mentioned in Jpn. Pat. No. 3337677.